1. Field of the Invention
This invention relates generally to electrical connectors, and particularly to an electrical communication connector constructed and arranged to compensate for cross talk among signal paths carried by the connector.
2. Discussion of the Known Art
There is a need for a durable, high frequency electrical communication connector that compensates for or reduces cross talk among signal paths carried by the connector. As broadly defined herein, cross talk occurs when signals conducted over a first signal path through a pair of mated connectors are partly transferred by electromagnetic coupling into a second, adjacent signal path through the mated connectors. The transferred signals become "cross talk" in the second signal path, and they act to degrade any signals that are being routed over the second signal path.
For example, an industry type RJ-45 electrical communication connector has four pairs of terminals for carrying four different signal paths. In typical RJ-45 plug and jack connectors, all four pairs of conducting terminals extend closely parallel to one another over the lengths of the connectors. Thus, cross talk may be induced between and among different signal paths through the typical mated RJ-45 connectors. The induced cross-talk also becomes stronger as signal frequencies or data rates increase.
One known arrangement for compensating a connector for cross talk induced among terminals of the connector, uses a multi-layer board having printed wire traces that are aligned vertically with one another on different layers of the board. The traces are selectively connected to the terminals of the connector, and operate to compensate for (i.e., to cancel or reduce) cross talk that would otherwise develop at the connector terminals. See U.S. patent application Ser. No. 08/668,553 filed Jun. 21, 1996, and assigned to the assignee of the present invention and application. All relevant portions of the '553 application are incorporated by reference herein.
The above described multi-layer board arrangement may be applied to a communication jack connector, to compensate for cross talk originating from an offending, uncompensated mating plug connector. In one arrangement, the board traces are electrically connected to certain jack terminals at locations where the terminals connect with outside circuits or cable wire leads. See U.S. patent application Ser. No. 08/904,391 filed Aug. 1, 1997. See also application Ser. No. 08/923,741 filed Sep. 29, 1997. Both of the '391 and the '741 applications are assigned to the assignee of the present invention and application. All relevant portions of the mentioned applications are incorporated by reference herein.
U.S. Pat. No. 5,647,767 (Jul. 15, 1997) shows a connector jack assembly having network signal conditioning components such as choke coils, filter circuits and transformers, connected in series with contact terminals which engage a mating connecting plug. The components are arranged on a printed circuit board with contact pads on both sides of the board.
Wired communication links and networks are now being called upon to support data rates not just up to 100 MHz or industry standard "Category 5" performance, but up to as much as 250 MHz or "Category 6" performance levels. For the latter, the above described arrangements for reducing connector-induced cross talk have not proven adequate, however.